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The loopback condition imposed in all cases is a logic
level loopback at the point within the H4TU-C where
the DSX-1 signal passes into the HDSL4 modulators.
Figure 4 depicts all of the loopback locations possible
with ADTRAN HDSL4 equipment.
H4TU-C Network-Side Loopback
DSX-1
H4TU-C
H4TU-R Network-Side Loopback and/or
H4TU-R NIU Loopback
DSX-1
H4TU-C
H4TU-R Customer-Side Loopback
X
DSX-1
AIS
H4TU-C
H4TU-C Customer-Side Loopback
X
DSX-1
AIS
H4TU-C
H4R Network-Side Loopback
DSX-1
H4TU-C
H4R Customer-Side Loopback
X
DSX-1
AIS
H4TU-C
H4R1 Network-Side Loopback
DSX-1
H4TU-C
H4R1
H4R1 Customer-Side Loopback
X
DSX-1
H4TU-C
H4R1
AIS
H4R2 Network-Side Loopback
DSX-1
H4TU-C
H4R1
H4R2 Customer-Side Loopback
X
DSX-1
H4TU-C
H4R1
AIS
X = Signal Inactive
Figure 4. HDSL4 Loopbacks
In addition to network-side loopbacks, the H4TU-C
provides customer-side loopbacks initiated by using
either the terminal control port or in-band loop codes
(see Appendix A). In this mode, an AIS signal is
supplied to the network.
6
AIS
LOCAL
DS1
LOOP
X
H4TU-R
AIS
LOCAL
DS1
LOOP
X
H4TU-R
LOCAL
DS1
LOOP
H4TU-R
LOCAL
DS1
LOOP
H4TU-R
AIS
DS1
X
H4R
H4TU-R
DS1
H4R
H4TU-R
AIS
DS1
X
H4R2
H4TU-R
DS1
H4R2
H4TU-R
AIS
DS1
X
H4R2
H4TU-R
DS1
H4R2
H4TU-R
5. CONTROL PORT OPERATION (HDSL4)
The 220 H4TU-C provides a front panel DB-9
connector that supplies an RS-232 interface for
connection to a controlling terminal. The pinout of
the DB-9 is illustrated in Figure 5.
1
6
2
7
3
8
4
9
5
Figure 5. RS-232 (DB-9) Pin Assignments
The terminal interface can operate at data rates of 1.2,
2.4, 4.8, 9.6, and 19.2 kbps. The asynchronous data
format is fixed at 8 data bits, no parity, and 1 stop bit.
The supported terminal type is VT100 or compatible.
The H4TU-C supports two types of terminal
emulation modes. The manual update mode is a dumb
terminal mode, where the user can use print screen
and log file commands easily. This mode also
includes a "3 SPACES TO UPDATE" message on the
top of the terminal screen (pressing the spacebar three
times to update the screen). The real-time update
mode enables all screen highlighting and cursor
placement. Print screen and log file commands are
not available in this mode. The default terminal mode
is real time update mode.
NOTE
Pressing the
C
T
TRL
toggle between manual and real time
terminal modes.
NOTE
Pressing
while on any screen to go back to
E
SC
the previous screen.
TXD (Transmit Data)
RXD (Receive Data)
SGN (Signal Ground)
while on any screen to
61222401L1-5C
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